Telecommunications systems, cable television systems and data communication networks use optical networks to rapidly convey large amounts of information between remote points. In an optical network, information (“traffic”) is conveyed in the form of optical signals through optical fibers. The optical signals may comprise a beam of light having a specific wavelength and having the traffic modulated onto the beam. In some instances a wavelength configured to carry information may be referred to as an “optical channel” or a “channel.” Each channel may be configured to carry a certain amount of information through an optical network at a particular data rate.
To increase the information carrying capabilities of an optical network, multiple signals transmitted at multiple channels may be combined into a single optical signal. The process of communicating information at multiple channels of a single optical signal is referred to in optics as wavelength division multiplexing (WDM). Dense wavelength division multiplexing (DWDM) refers to the multiplexing of a larger (denser) number of wavelengths, usually greater than forty, into a fiber. WDM, DWDM, or other multi-wavelength transmission techniques are employed in optical networks to increase the aggregate bandwidth per optical fiber.
An optical network may be configured to operate within a particular transmission band of the optical spectrum. For example the transmission band in North America may be referred to as the C-band and may include optical wavelengths between approximately 1525 and 1565 nanometers (nm). In some optical networks, the spectral spacing of channels may be fixed such that the number of channels within the transmission band of an optical network may also be fixed. Additionally, the channels may have a maximum data rate that limits the amount of traffic that may be sent per channel. Accordingly, the maximum capacity of an optical network may be limited by the fixed maximum number of channels within the transmission band of the network and the maximum data rate per channel.